A model of the Delta Clipper Experimental or DC-X built by McDonnell Douglas as a test vehicle for a reusable SSTO concept - it's a vertical hovering and landing test vehicle comparable to the grasshopper Space X built to test the technologies for the Falcon 9 although the intended final version would have been a reusable SSTO rocket the model is full scale but designed to be scaled down about 1/100 and printed easily